Aqueous Solutions of Ionic Liquids: Microscopic Assembly. Issue 3 (17th December 2015)

• Record Type: Journal Article
• Authors: Vicent‐Luna, Jose Manuel; Dubbeldam, David; Gómez‐Álvarez, Paula; Calero, Sofia
• Is Part Of: Chemphyschem. Volume 17:Issue 3(2016)
• Page Start: 380
• Page End: 386
• Publication Date: 2015-12-17
• Subjects: hydrogen bonds -- imidazolium -- molecular dynamics -- ionic liquids -- structure of water; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201501022
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure–property relationships of such systems is hence desirable. One of the crucial molecular‐level interactions that influences the macroscopic behavior is hydrogen bonding. In this work, we conduct molecular dynamics simulations to investigate the effects of ionic liquids on the hydrogen‐bond network of water in dilute aqueous solutions of ionic liquids with various combinations of cations and anions. Calculations are performed for imidazolium‐based cations with alkyl chains of different lengths and for a variety of anions, namely, [Br] −, [NO3 ] −, [SCN] −, [BF4 ] −, [PF6 ] −, and [Tf2 N] − . The structure of water and the water–ionic liquid interactions involved in the formation of a heterogeneous network are analyzed by using radial distribution functions and hydrogen‐bond statistics. To this end, we employ the geometric criterion of the hydrogen‐bond definition and it is shown that the structure of water is sensitive to the amount of ionic liquid and to the anion type. In particular, [SCN] − and [Tf2 N] − were found to be the most hydrophilic and hydrophobic anions, respectively. Conversely, the cation chain length did not influence the results. Abstract : What a solution ! A detailed study of the structure of water containing low concentrations of ILs, for ILs with a variety of anion types and with cations having a range of alkyl‐chain lengths using molecular dynamics simulations with validated atomistic descriptions and intermolecular interactions was presented.